Make your own straw and mud brick, and see how hard it is to do. Check the time before you start so you can see how long it takes you to create a finished brick.
First, put some soil into a bucket or other plastic container. Add water and mix it with the soil until the mixture is squishy but not like a liquid. Mix it all up well to get rid of any dirt clods. Then get some grass clippings (or straw, if you have it). Chop or tear the grass into little pieces. Make it so your mixture is roughly half grass pieces and half mud. Mix that all up well, and let it sit somewhere out of the way for about a day.
The next day, pour off any excess water. Then get some smaller containers (plastic sandwich/lunch containers might work well) and poke some scattered holes in the bottom of them with scissors (be careful and ask a parent for help). These will be your brick shapers. Your work area might get dirty, so be sure to protect any surfaces by putting newspaper or cardboard down first (or just go outside). Squash your mud mixture into the brick shapers. Shake the container a little from side to side to make the top of the mud even. Then let the container with your soon-to-be brick in it sit out in the sun to dry. Water will drain out through the holes. It might take a whole day (or longer) for the brick to dry.
When the brick is dry to the touch and looks dry on the bottom too, use a butter knife to go around all sides of the brick to loosen it from the sides of the container (if needed). Turn the container upside down with one hand on the top and one on the bottom. Your brick should fall out of the brick shaper.
Check the time and see how long it took just to make one finished brick. Now imagine what it would feel like if you had to make bricks all day every day for as many hours of the day as you could. How many bricks do you think you could make?